1. Field of the Invention
The present invention relates to a document type recognition apparatus, an image forming apparatus, a document type recognition method, and a computer program product.
2. Description of the Related Art
The high-compression PDF is known as a technique for increasing the compression rate and the image quality in the PDF. The high-compression PDF is known to separate an image into image regions, i.e., the character region and the pattern region, to apply compression processing (for example, MMR or JPEG) suitable for each of the character region and the pattern region, thereby achieving high compression.
Furthermore, the technique for determining the attribute of an entire document is typically said to be the document type recognition technique. It is also known that at the time of creating a high-compression PDF file, the document type is determined by the document type recognition technique to thereby switch processing to suit the document type (for example, to select the threshold value for binarizing processing or an appropriate compression method).
At the time of creating a high-compression PDF file, the following document types are expected to be improved in image quality by switching processing to suit the document type determined by the document type recognition technique.                Character only document        Newspaper document        Pale document        
In particular, due to a recent upsurge of interest in environmental awareness, such a case has been increased in which copiers output copies in a toner-save mode when reproducing images. When an image outputted in the toner save mode as mentioned above is scanned as a document so as to create a high-compression PDF file, the document is naturally “a pale document.”
However, known document type recognition techniques require determination circuits for each document type, thus causing high processing costs. Furthermore, known document type recognition techniques and compression techniques supports “the character only document” and “the newspaper document,” but does not support another document type (for example, “the pale document”).